Re-design your boat drains and thru hull fittings.

noswellplease

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I recently met a very knowledgeable gent who was returning home after a lengthy trip on his sailboat. He has worked on boats professionally for the last 30 years and he made the following suggesions! What do you think?
He said my deck and cockpit drains should be re-designed and simply let drain somewhere above the waterline, and not as they are presently lower down below the waterline, you can also use nylon and no need for bronze or whatever.
Water inlet, he just uses one, this feeds the engine and he then taps off to feed the heads. The heads discharges just above the waterline which he says is not a problem. Thats his system for what its worth. I guess it reduces the need for all those potentially dangerous thru-hull fittings below the waterline. My question, is it worth going this route with all the work and expense involved? I am hoping to do a little serious crusing at some time in the furure and what he says appears to make sense. What do others think?
 

gandy

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I'm no expert, but I wouldn't want my cockpit drains to go below the waterline, as I would then need to leave their seacocks open at all times. I like seacocks shut unless they're needed, and always shut when we're asleep or the boat's unattended.

Presumably yours go underwater to avoid stains on the topsides.
 

Evadne

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They might be like mine, which exit below the waterline in order to drain at all, because the cockpit sole is only an inch or three above the waterline.
 

fireball

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Cockpit drains to above the waterline are superb ... if your cockpit floor is high enough to give you a decent drain angle - and preferably over the transom rather than the sides.... we've got 2 x 3" tubes out the back of ours ... I would say it keeps the cockpit clear of water ... but we don't tend to take too much in.

As for a single water inlet ... I can see the advantage ...

My view is that unless you are doing a substantial refit or planning extended sailing, or in the case of cockpit drains - have a particular problem, then it is probably not worth the effort involved in making the modifications.
 

jenku

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Mine do and have done so since 1975 without sinking the boat. I have read somewhere that the kind of drains that go straight down to the water drain faster than the above waterline transom kind as they have bends in them. Don't know if that's true.

That said, if I did not have those thru-hulls down there I could leave the boat in the ice during the winter. Don't dare do that now, but that's the only drawback I can see. Hardly a problem for you though I reckon. /forums/images/graemlins/cool.gif
 

Salty John

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Good advice. If the cockpit floor is significantly higher than the waterline then the drains can discharge above the waterline, preferably through the transom. One-way flapper valves can be used to prevent water running back up the drains.
By using a 'seachest', a stainless steel manifold, you can bring raw water in through one sea cock and distribute to several pumps. You can also use it the other way, draining everything to the seachest which discharges via one seacock. It's not recommended you discharge the bilge pump via this route, however.
 

DJE

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A branch off the engine cooling water inlet to serve the toilet inlet on my boat would require a hose about 12 feet long. That hose would be exposed to sea water pressure all the time the engine was running. I think that would create more risk than is avoided by having an extra seacock. Provided the seacocks are good quality and properly installed, and that you shut them when not in use, I don't see how two can be more dangerous than one.
 

Blueboatman

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If you can do it consider bonding rigid fibreglass tubing from each hole up above the waterline and fitting the relevant seacock at that point above sealevel.
Not always possible and the pipe has to be pretty darned strong and located where you are absolutely certain that it cannot be sheared off by some shifting object in the event of a knockdown..but this idiotproof k.i.s.s. concept has always worked for me!
 

john_morris_uk

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[ QUOTE ]
I'm no expert, but I wouldn't want my cockpit drains to go below the waterline, as I would then need to leave their seacocks open at all times. I like seacocks shut unless they're needed, and always shut when we're asleep or the boat's unattended.

Presumably yours go underwater to avoid stains on the topsides.

[/ QUOTE ]

On our boat, the cockpit drains HAVE TO exit underwater, as we have a centre cockpit. I have no problem with leaving them open all the time.

Are you really so paranoid about sinking that you close all your seacocks before you go to bed? Thousands of boats sail thousands of miles across oceans with some/most of their seacocks open all the time. I suggest that many seacocks are there to close when something goes wrong.

For example I might argue that its safer to leave the engine one on all the time when you are onboard, so that the engine is 'ready to go' when required.

I check our seacocks regularly. They are free to move and ready to use. They are all double clipped and I use the highest quality hose on them. They have wooden conical bungs tied near them in case of emergency. Many of them stay open nearly all the time.

I sleep very soundly when onboard, whether we are at sea or at anchor.
 
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[ QUOTE ]
I suggest that many seacocks are there to close when something goes wrong.

[/ QUOTE ]

Sounds about right.

Is it too 'dumbing down' to encourage all to check frequently that their seacocks actually do close off the oggin when needed, and that skin fittings/hoses/wormdrive fittings are not corroded or damaged? The RNLI and MAIB have frequent cause to comment on the results of failed through-hull openings - always through a lack of inspection.

And the other vulnerability - a great big cockpit and tiny little half-blocked cockpit drains that would take half-an-hour to drain, after one of a series of lumpy seas ( they don't come in one's ) jumps unasked on board.

/forums/images/graemlins/wink.gif
 

pappaecho

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The two cockpit drains on my Evasion 32 have no seacocks and are fibreglassed tubes directly to the twin outlets under the stern. Any water which does come over seems to disappear quick enough.
I can see that a single seacock feeding engine at the back and heads at the front is worth the effort. On the heads you still have to have an outlet
 

richardandtracy

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I'm in the no holes camp.
I built my Spray with an air cooled motor, transom drains and a Porta-Potti tanked toilet. The drive from the motor was by chain up above the W/L, into a layshaft and then down to the prop shaft by chain again in a sealed well of only 36in^2 cross sectional area. This meant I effectively had no underwater openings.
Then I became broke after moving house to satisfy SWMBO & never got the chance to live with it. I can see there'd be problems with the toilet - but I'd rather live with that than a nagging fear of the boat going 'glug' at me.

Regards

Richard.
 

john_morris_uk

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[ QUOTE ]
I'm in the no holes camp.
I built my Spray with an air cooled motor, transom drains and a Porta-Potti tanked toilet. The drive from the motor was by chain up above the W/L, into a layshaft and then down to the prop shaft by chain again in a sealed well of only 36in^2 cross sectional area. This meant I effectively had no underwater openings.
Then I became broke after moving house to satisfy SWMBO & never got the chance to live with it. I can see there'd be problems with the toilet - but I'd rather live with that than a nagging fear of the boat going 'glug' at me.

Regards

Richard.

[/ QUOTE ]Words fail me! Is this a troll? If it isn't, have you ever noticed that your thoughts about underwater openings flys in the face of 99.99% of all boats and ships on the water. I respect your right to your opinion, but may I suggest that you do some risk assessment? My opinion is that you are more likely to sink from hitting something at night or be run down by a madman than sink through skin fitting failure if the boat is maintained properly.

When was the last time you heard of a boat sinking through having a fitting fail? There have been a couple, but I suggest that the boats were not maintained or looked after.
 

jenku

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It may very well be a statistics misreading leading to this thru-hull fear. I remember quite some discussions on the web a while ago about statistic (I think from USA) claiming that a majority of boats that sink at their moorings do so because of seacock or thru-hull failure.
People then don't realise that most boats that sink do not do it at their moorings and thus not due to seacock failure either.
 

gandy

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[ QUOTE ]
Are you really so paranoid about sinking that you close all your seacocks before you go to bed?

[/ QUOTE ] Maybe you're right and it is over cautious. The engine seacock is the only one that's not readily accessible as it lives under seat cushion. The sink drain and toilet seacocks are so easily reached that it seems sensible (to me) to close them after use.

I turn the gas off at night as well, not because I really think there'll be a gas leak.

Who was it who said "paranoia keeps me sane"?
 

roly_voya

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Re: Re-design your boat drains and thru hull fittings. - the obviouse

Like most traditional boats I have 1.5" cockpit drains exiting under the cockpit, my only worry is weather they are big enough. I also have several other exits underwater so I have done 2 things
First they are all proper bronze fittings (all but one blakes plug type), are turned on/off regularly to stop them seizing and serviced anually which is the big advantage of the plug type fitting, you cant strip or adjust a ball valve.
Second I fitted a big bilge pump (8000g/h 3" discharge) and to test it I have opened the largest and deepest seacock which is a 1.5" hose about 2ft underwater and checked that the pump will cope, it does comfortably shutting off every few min while the bilge refills. I also fitted an alarm to the circuit but wasn't needed as you could not hear it for the noise of the pump!
I think this is a seriouse point, most boats seem to have tiny bilge pumps that only aim to keep out a bit of rain and spray. The bilge pump is there to stop you sinking due to failure or collision or at least to give you time to abondon ship in good order
 

alan006

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Just a though about plastic skinfittings. I have seen a plastic skinfitting sheared off flush to the hull when a boat was being lifted out and the strop covered the fitting. This would not have happened if the fitting was bronze. I am very doubtful about plastic skinfittings and have always used bronze. Apart from the cost what benifit would plastic have over bronze?
 

alec

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These days, a new yacht of about 50 feet will probably have 12 to 18 holes in the bottom of the boat. I have often counted them myself.

My own boat has the cockpit draining into two seacocks along with water running off the decks. As mentioned, the seacocks have to be left on, and the difference between me and Neptune is about 6mm of plastic pipe.

I don't know what insurance companies base their risk on this type of thing but hitting ships and rocks probably comes much higher.

I think provided we keep a watchful eye on the weak points on boats the likelyhood of bad things happening is possible but remote.

I notice that window cleaners don't use ladders anymore but are risking their necks looking up all day with very long brushes. I feel we are in a far better position to look after our own health and safety and long may it continue.

The Health and Efficiency boys probably mean well, but sailing and boating is probably the last outpast where we are still in control.
 

noswellplease

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Thanks for all the replies....much food for thought. Deck and cockpit can be re-designed for above waterline draining which would remove two potential hazards low down in the bilge. I had a problem with water ingress from a bolt which came loose on the cutless bearing and hence my new found paranoia! Now I don't trust boatyards, chandliers, and a few other groups who claim to have all the answers. If I can make things a bit safer aboard well, then it's an improvement.
Cheers Russ
 
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